Hundreds of people in southern Ohio who say a DuPont chemical plant across the Ohio River contaminated their water and caused their health problems are suing the company in federal court in Columbus.

They say that C8, a chemical used to make Teflon at the Washington Works plant in Washington, W.Va., caused their health problems.

High levels of C8 have been found in water supplies near the plant along the Ohio River, and residents of the area have been fighting with DuPont about the contamination for more than a decade.

A science panel set up as the result of a class-action lawsuit concluded that there is a probable link between the chemical, also called perfluorooctanoic acid, and a number of health issues. They include testicular and kidney cancers, pregnancy-induced hypertension, thyroid disease, high cholesterol and ulcerative colitis, a type of inflammatory bowel disease.

Those conclusions, made in the past two years, led to lawsuits against DuPont in December in state courts. The cases were moved to federal court this month at DuPont’s request.

Debra Nelson, one of the attorneys for the plaintiffs, said 26 cases are in federal court in Columbus; 10 others are in federal court in West Virginia. But she expects hundreds of people to file personal-injury claims in the next year or so.

“So many people don’t even know this is going on yet,” said Nelson, of Huntington, W.Va.

As part of the class-action suit, DuPont agreed that anyone who was diagnosed with the health conditions linked by the panel to C8 could pursue a personal-injury claim if they had lived in the water district for at least a year.

Those are the lawsuits now in federal court.

Each asks for compensatory and punitive damages and payment of plaintiffs’ costs for the injuries caused by DuPont’s “reckless and negligent” contamination of human drinking-water supplies.

The complaints contend that DuPont knew long before 2001 that high levels of C8 were in the water near the plant and that its plant was discharging C8 into the river. The company concealed that knowledge from the public and its customers, the complaints say.

Nelson said the plaintiffs include plant employees as well as area residents.

The scientific panel studied data collected from about 70,000 residents.

DuPont has installed filters to keep C8 from contaminating water in the area. Spokesman Dan Turner said in a statement that DuPont “will vigorously defend against any and all such lawsuits not based upon valid science.”

He said that “lawsuits such as these ignore family history and lifestyle choices as a primary cause of health issues and disease in specific individuals.”

The company has agreed to phase out its production and use of C8 by 2015.